I think what will ultimately be discovered is that there's a group of depressed suicidal patients whose depression is so disabling that they're unable to carry out their self-destructive desire. As they begin to respond to the anti-depressants they recover their ability to act before they lose their desire to act.
Essentially, we're taking suicidal people who lack the energy to kill themselves and making them more energetic.... with predictable results. Sort of like giving taxi fare to the nearest span to a broke bridge-jumper.
Damn pills. Flush them all. Get up and go do some yard work, for heaven's sake. Works for me.
All this crude talk about "energizing" is like unto the way the old natural philosophers thought of fire, air, earth, and water. Nobody has even begun to reverse engineer the marvel we know as "thinking."